Reciprocating motor



Aug. 14, 1928.

l C. S. WEYANDT RECIPROGATING MOTOR Filed Feb. l, 1926 3 Shee'LS-Shee. 1

3 Sheets-Sheet 2 INI/EN TOR.

L ATTORNEY.

Aug. 14, 1928.

c. s. WEYANDT RECIPROCATING MOTOR Filed Feb. l, 1925 Aug. 14, 1928.

C. S. WEYANDT RECIPROGATING MOTOR Filed Feb. 1, 1926 5' Shams-Sheet v INVENTOR.

- ATTORNEY.

Patented' Aug. y14, 1192s.

^ UNITED vSTATES- PATENT orifice.`

i CARL S. WEYANDT, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO4 CENTRAL ELEC- TRIO TOOL COMPANY, 0F PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENN- ancrraocn'rme Moron,-

Application iled. February .1, 1926. Serial No. 85,245.-

My invention relates to electric motors of the reciprocating type, particularly such as are utilizable as permissive-*tools for drilling, cutting, chipping, riveting or otherwise working metal, stone, concrete and the like, and particularly for tamping railway ballast, or earth, as around poles or postsfor such as backfill in ditches.

In accordance with my invention, a tool of the characterreferred to is provided with a handle at or adjacent one end of the motor or motor casing, and the several currenti conducting leadsextend to,or adjacent the Aao handle or handle structure insuch relation to the buffer spring which lies axially beyond the motor or the point to lwhich the conducting leadsextend, that the buffer spring may bereplaced or repaired without Idisturbing the conducting leads; more par. ticularly in accordance with my invention, a tamping o'r similar tool, of the character referred to, is provided with'two handles, one of them the aforesaid handle at or adj acent the end of the motor or motor casing, and which constitutes a side handle, and an upper or top handle more remote from the motor so disposed with respect to the side handle that the buffer spring lies betweenthe upper and side handles.

Further in accordance with my invention, in a tool of the character referred to, where .high power long strokes, generally at low frequency, are required, as in ballast tamping, riveting, etc., the weight of the moving system is made small in order that there shall be as little lag as possible instarting and during acceleration, so that the velocity attained just before impact shall be as high 'as possible for, as between weight or mass and velocity, weight or mass maybe to some extent sacrificed in favor of velocity, since the kinetic energy at impact is directly proportional to the Weight or mass, and proportional to .the square of the velocity. The reduction of mass or weight is in part obtainable by utilizing a relatively short magnetizable core, and by bringing the air. gaps of the magnetic circuits of the operating windings close to each other; and in a composite moving system, comprising a magnetizable core proper, in addition to guide rods thereon, the ratio of the weight of the 'magnetic core itself to the weight of the composite system, comprising core and guide rods, is made small to ensure reduction of slip or to ensure-early starting. The magnetic core proper may be further lightened by a circumferential groove lor grooves between its ends, particularly a groove of considerable length midway between the core ends, such groove or grooves having 'the further advantage of increasing' the'rluctance wlthin the air gap path itself between pole tips, butthis reluctance should not be'i'ncreased to the point of allowing flux to pass from'pole tip to pole tip outside of the magnetic core, and so in effect take a leakage path. In any event, the reluctance of the flux path in. the core should not be so great as to effect excessive'saturation.

Further in accordance with my invention, the moving system may comprise a magnetic core member proper having thereon guide rods of non-magnetic material, Vwhose impact ends-are shod with hard impact-withstanding metal, as Stellite or equivalent.

Further in accordance'with my invention,

guide bushings in which the aforesaidl guide rods bear are preferably provided with external recesses or circumferential grooves containing fibrous orl equivalent material saturated with lubricant which is slowly delivered tothe internal guide surface through .lsuitable passages. 4 x Further 1n accordance with my inventlon,

`in, a reciprocating motor in which the moving system 1s enclosed 1n a. tube or barrel to which lamlnations of the lnagnetlc c1rcu1t are held by clamping structure,y the waste of energy byl current induced by the fluctuating magnetic field is reduced by slotting thev barrel and/or clamping structure in such positions and to such extents as to materially interruptor greatly lengthen the paths in which currents would be induced, and more particularly, the slots in the clamps and barrel are brought substantially into register with each other.

Further in accordance with my invention, an air gap, with respect to which the reciprocating core moves, is disposed nearer one than the other of groups of magnetizableelements spaced fromv each other longitudinally of the movement of the core, and more partlcularly where the core coacts w1th a plurality of air gaps spaced from each other longitudinally of the movement of the core, the elements making up the magnetic circuits are so disposed that the longitudinal spacing of the air gaps is diminished, whereby there may be utilized a core of less weight operating at higher velocity.

Further in accordance with my invention there is provided exteriorly of the motor unit itself, a buifer structure to eii'ect easy replacement if broken, and to reduce likelihood of breakage by distribution of impact.

Further in accordance with my invention, a structure is provided embodying guide bearings forthe core or reciprocating element of an electric motor, whereby .frictional losses are diminished and) the wear on the internal motor structure is substantially reduced.

Further in accordance with my invention, a stop member subject to impact of the reciprocating element bears against the resilient buffer structure', and is provided with means for ermitting passage of lubricant therethrough.

Further in accordance with my invention, particularly in electric tampers or the like, that end of the tamper bar or other tool which receives the impact of the moving system is in such position with respect to the moving system of the motor, when the tool is in its lowermost position, as when the tool is raised from the work, that the magnetic core may not pass too far out of the magnetic field, with the result that the moving system will continue to reciprocate continuously even when the tool is withdrawn or raised from the Work Further in accordance with my invention, for long high power strokes, particularly. in lthe case of a tie tamper, there is utilized alternating current of low frequency, from about 15 to about 27 cycles per second, with an optimum of about 20 or 21 cycles per second; and further in accordance with my invention, in the utilization of such low frequency in the production of long high power strokes, the highest efficiency is obtainable when utilizing a light moving system, of which the magnetic core proper is short, in association with air gaps closely approaching each other, and when the parts' are -otherwise proportioned generally as hereinafter described.

Further in accordance with my invention, the barrel or tubular member within which the moving system is disposed is constituted of metal which is light in weight and yet of great strength, such as an aluminum alloy, .so reducing the Weight of the tool, and, more particularly, because of its relatively high specific resistance reducing the losses repre-I sented by currents, including eddy currents,V

induced in the tubular member by the fluctuating magnetic field in which it is positioned; and further in accordance with my mvention, other parts of the motor structure, such as the members which clamp the laminations, and the members upon the barrel or tubular member, are similarly preferably made of like alloy.

VFurther in accordance with my invention, the Wire or conductor constituting the motor windingor windings is of aluminum, thereby greatly decreasing the weight of the motor and the'incrtia of the windings, and in addition, because of the greater resistance of the Winding as compared with one of copper, the ratio of resistance to inductance of a motorwinding isincreased, thereby increasing the power factor, and, particularly when laminations are common to the two `magnetic circuits, the overlap of the magneto-motive-forces impressed upon the common laminations is reduced, and the losses inthose laminations are reduced.

This application is in part a continuation of my application Serial No. 19,311, filed March 30, 1925, in which are made claims to the particular exteriorly disposed spring buffer structure and the lubricating core stop therein disclosed, while herein are made claims generic tothe `disclosures of both applications and claims specific to the particular buffer structure and lubricating core sto herein disclosed. n

y invention resides in features, structure, arrangement, combination, proportions and operation of the character hereinafter described and claimed.

For an illustration of one of the various l forms my structure may take, and of several modes of use, reference is to be had to the accompanying drawings, in which:

Fig. 5 is a fragmentary horizontal sectional. view,.largely in plan, taken onthe line 5-5 of Fig. l.

Fig. 6 is a horizontal sectional. View, partly in plan, taken on the line 6-6 of Fig. 1, and on line 6-6 of Fig. 7.

Fig. 7 is a fragmentary plan view of the barrel andl pole tips, developed into a plane.

Fig. 8 is a diagrammatic view of `circuit arrangements utilizable with a plurality of reciprocating motors for effecting blows either in phase with each other, or dephased.

Fig. 9 is a plan view-of. a railway tie with a plurahty of tampers operating thereon.

Fig. 10 is aview, partl in section, illustrating the application o my invention to rlvetmg.

Referring to the drawings, 1 a, barrel 13 or tubular member, of metal, such ias brass or bronze, and "preferably of a light weight alloy, as an-aluminum alloysuch as duraluinin, of sufficiently high tensile strength, for

l the alloy is relatively liigh.

through openings in the member 1, the inlner ends vof the laminations coming flush Disposed upon the exterior of the member 1 are the circumferentially disposed groups of laminas 2, 3 and 4, of silicon steel or other suitable magnetic core material. The central laminations 3 are common top the magnetic circuits of the two windings or solenoids 5 and 6, and, as indicated in Figs.

4 and 6, are comprised in a series of circum.

ferentially arranged groups whose inner ends rest upon the iiat external sides of the member 1. The ilaminations 2 and 4 are similarly disposed in circumferential groups upon external iiat surfaces of the member 1.

As indicated in Figs. 1 and 7, the inner ends or pole tips of the laminations extend with the inner cylindrical wall of the'mem'- ber, thereby extending further than heretofore toward the axis of barrel 1'. As lindicated, these pole tips 2L of the laminations 2 and the pole tips '4a of the laminations 4 may have greater length, axially of the member 1, than the pole tiprs 3b1 of the com? mon or central laminations 3. r

Furthermore, the pole tips- 2a and 4a extend a considerable distance toward the pole tips 3, thereby bringing close together the two air gaps one of them between the pole tips 2a and 3, and therother between the pole tips 4a and 3a. So bringing the air gaps'close together permits the use of a relatively shorter inagnetizablel reciprocating core member 24, thereby contributing to a light movable core or core system, making possible also' long and powerful strokes which Yare particularly advantageous `in lsome ,elds of use, such as the tamping of ballast around or under railway. ties, riveting, and other relations, and shorteninv the magnetic circuit of the -motor as a whole, and particularly through the reciprocating core member 24.

External to the member 1, andkiithe space between the laminations 2 and 3 and in the space between theflaminations 3 and` 4, are the clamping members 7 and' 8 of any suitable material, preferably a light alloy of suitably high specific resistance, such, for example, as tlie aluminum alloy constituting the barrel 1, whereby not only is the weight of the motor reduced, but the waste currents induced in the members 7 and 8 are decreased. The pole tip ends of the laminationsare bevelled as indicated, as also are the ends of the clamping members 7 and 8,

whichlatter are held by screws9, Fig. 6, to the barrel member 1.

The clamping members 7 and 8 are .circumferentially discontinuous, as indicated in Fig. 6 respecting members 7, there being field. In addition, locally, as between the lamination .prolev tips, the barrel -1 is slotted at 10, as indicated in Figs. 6 vand 7, siini.

larly for the purpose of reducing the waste currents induced in the barrel.. member 1, and. particularly by increasing the length of the path that any currents induced must take. As indicated in Fig. '6, the. gaps between neighboring clampingV members, vas 7,

and the slots 10 in the barrel 1,-;are substantially in register,N in the sense that they are so positioned with respect to each other that the circutous path for induced currents in the barrel and to the clamping member and return to the barrel is broken up and short# ened. The discontinuity of the clamping members, and the slotting of the barrel 1 both contribute to-reduction of induced current losses, and' these losses are further minimized by bringing tlie slots 10 and the gaps between Athe clamping members into a relaf tion ofthe character indicated in Fig. 6.

' The member or barrel 1, the laminations 2, 3 and 4, and the windings 5 and 6, constitute a unit separately assembled as such. At its opposite ends the barrel 1 has portions 11 and -12 of greater diameter. Upon the member 11 is threaded the annular nut 13 constituting a somewhat beveled abutment against whichengage complementar-ily beveled edges of the laminations .2. 'Upon the member-12 is similarly threaded and beveled an annular nut 14 thrusting against the complementarily beveled laminat-ions 4, holding 'the d iierent groups of laminations as a unit upon the barrel and causing` the beveled edges of the clamping `members 7 and 8 to engage orA be engaged by the associated beveled laminations, the beveling of nuts and laminations forcing the laminations i toward the barrel 1. .The Winding 5 is held between the laminations 2 and 3, and winding 6 be,v

`tween laminations 3 and 4, and the windings constitute withthe laminations?, 3, 4, clamps 7, 8 and barrel 1 a unit which isV removable as such from the motor structure.

An enclosing casing,15,'of silicon steel or other suitable magnetizable material, is comprised in the magnetic circuits and is cnlower end of the` member 12 of the barrel 1 and abutting against the annular nut 14, and having an annular beveled rib 17 abutting against the complementarily beveled end of.

the casing 15.

At the upper end of themotor there engages upon the upper end of the annular nut 13 a member 18 whose outer and lower end is beveled to engage the complementarily beveled end of the casing 15. Member-18 -is preferably of libre or fibrous material which, because of its resiliency, flexibility or slight compressibility, makes possible compensa-v tion for unevenness or tolerances in the various parts clamped together. f Upon the upper side of the member 18 engages the upper end plate or closure member 19, attached to or integral with which is the side handle structure comprising the members 20, 20 and the hand grip 20a, all in a plane normal to the path of movement of core 24. Through the members 16 and 19 pass the longitudinally extendingV tie rods 21, upon whose lower ends are threaded the nuts 22 and upon whose upper ends, engaging the member 19, are threaded the nuts 23. Taking up proacliing air gaps above referred to.

upon the nuts draws the members 16 and 19 forcibly towards each other, thereby clamping members 16 and 18 to the casing 15 and also holding .the aforesaid unit, comprising barrel, laminations, clampsl and windings, in fixed position within the casing 15.

The reciprocating core 24 consists of silicon steel or other suitable magnetizable material, relatively short when utilized in a long stroke motor, and particularly when utilized in (1o-operation with closely apn the example illustrated, tlie core 24 proper does not bear upon tlie inner wall of the barrel 1, but is carried by guide rods 25 and 26 extending at their adjacent ends into bores in the member 24 and welded thereto at 27, by any suitable welding material, as suitable iron or equivalent. The, rods 25 and 26 are of non-magnetic material, preferably f non-magnetic steel, such as manganese steel CII containing suiiicient manganese, as of the order of 11 to 13 per cent, to render the material non-magnetic. Or these members may be of rezistal, a non-magnetic alloy of iron,

' nickel, "chromium and silicon. The rod 25 is guided and reciprocates in the bearing bushing 28, and the rod 26 is guided and Ireciprocates in the bearing bushing 29, both 'bushings disposed and held within the barrel El. These bushings may be of any suitable material, as oilless bushings, such as wood or other suitable material impregnated with `or bronze bushing with a graphite liner or insert; or, as indicated, of solid metal, such as bronze, having external recesses, or peripheral grooves 30, in which may be dis posed waste or other fibrous material saturated with lubricant, which then passes inwardly to the bearing surfaces through suitable apertures, not shown. When the rods 25 are non-magnetic, as preferred, they are generally necessarily of a material which does not withstand impact or which may not be hardened by heat treatment or otherwise. Accordingly, upon the lower or impact end of the rod 25 and upon the upper or impact end of the rod 26 are welded orsecured disks 31, of Stellite or equivalent hard material which does not deform or yield under the impacts incidental to the use oi the motor.

'Ifhe lower bearingbushing 28 is held in position by the upper end of the tubular member 32,which is in turn held in place by Athe plate 33 held by the flange 34 of the tool holder 35 secured to the member 16 by bolts or cap screws 36, Fig. 2. The member 32 has a portion 32a of reduced diameter extending downwardly through the plate 33, and has a socket of polygonal cross section in which is received the upper end 37 of the tool shank, pf. similar polygonal .cross section preventing the tool from turn'- ing when in use. Upon the shank of the tool is tlie collar 3,8, which is confined between the lower end of the socket member 32a and the upper end of the bushing 39, through which the tool shank extends downwardly through the rubber buffer ,40 to the exterior and below the` aluminun or aluminum alloy tool holder 35, which is provided with the tubular steel liner 41.

4usual tamper shape 42, preferably curving slightly from axial alignment with the motor or' tool shank.

When the motor or tool as a whole is lifted away from the work, the tool will drop, causing the lower end of the collar 38 to rest upon the upper end of the bushing When in this position, tlie upper end of the tool shank 37 ispreferably in such position with respect to the air gap of the magnetic circuit, because of its length vabove the upper end of bushing 39,

that when engaged by the rod 25 the mag-v 32a will rest upon theupper sideof the collar 38 and will continue in engagement with the collar 38, except for the lifting effect upon the motor caused by the impact delivered upon the upper end of the member 37.

At the upper endof the motor, within the upper end of barrel member 1, which extends into the central boss 19a of member 19, is a bushing 43 abutting against the bearing bushing 29 and holding it in place.-

Engaging the upper end of the bushing 43V are the plates 44, secured to the member 19,

holding the bushing 43 and the bushing 29 in place,'the plates 44 being spring-like or lyielding if desired. They anvil or impact member 45, of hard steel or equivalent, taking the impact'of the moving system upon its return stroke, is short, light in weight, and extends partly into the bushing 43, within which the rod 26 freely passes, and is visible by the operator. A lubricating passage 45a extends transversely and longitudinally of the axis of said impact member from the exterior thereof and communicates y with the interior bearing surface of bushand beyond the end member 19 and side handle. structure 20, 4to or into which latter the several conductors 50 extend. The buffer being so disposed with respect to the end member 19 and particularly with respect to the handle structure 2O and the region or point to which the several conductors ex-u tend, the buffer spring is always in v1ew of the operator, who may immediately detect ibreakage which may be repaired without disturbing the end member 19, handle 20 or the conductors.

'Upon the tie rods 21, between the nut-s 51 and 49 thereon, is confined the plate 52, upon which is secured by the bolts 53 the stem 54 of the upper handle 55.

For tamping and like operations, the operator grasps the side handle 20-with one hand and the upper handle 55v with the other, the control of the motor being effected by a switch controlled by the lever 56, Fig. 3, positioned upon or adjacent the handle grip 20a'and operated by the hand which grasps the member 20a.

The arrangement above described is such that the buffer spring 47 is located between the upper handle 55 and the end member 19 or side handle 20.

affected by the'impacts` caused by the moving system, and these threaded elements are readily and cheaply replaceable should occasion require. f Referring to Fig. 8, there are shown alternating current supply conductors a, 6' and c, delivering polyphase alternating current, for example', a two phase current. The current for phase A is delivered, for example, by the conductors a and b, and the current forfthelphase B is delivered by conductors b and c. In the case of the usual two phase current, the electro-motive-force waves of the two phases are in quadrature.

Across the conductors a and b is connected the primary of a transformer T provided with two secondaries delivering current, respectively, to the filaments or cathodes f and f1 of thermionic valves whose anodes or plates are indicated at p and it under the railway tie 58, upon which are,

secured the rails 59. A similar motor M2 may be thrown into parallel with the motor M1, by closure of the switch 60, either.

through the same valves supplying motor M1 or through a separate valve system connected to the same phase, whereby the tamping tools 42 of the two motors will be simultaneously struck by the moving systems or plungers of the two motors.v This operation of the tamping or other tools` 42, in phase with each other, is of advantagein various relations, as in tamping, and, as

findicated in Fig. 10, for riveting, where the rivet sets lsimultaneously strike the rivet 62 for securing the plates 63 and 64 to each' other.

In tamping particularly this striking of the tamping tools at the same instants is of advantage, for the broken stone or ballast is the more readily andefiiciently compacted and forced into position under a tie. -This is particularly true when the two talnping bars-42 are used on opposite sides of and at the same end of a tie 58, which in Fig. 8 is shown in endv view. It is understood, however, that the tamping tools may be struck at the same instants, though they be applied in different relative positions with respect to the tie.

Where it 1s desired that the tools, such das tamping bars, rivet sets or any other type of tool in any field of application of the motors, shall be struck at different instants, the motors may be operated out of phase, so to speak, causing impacts upon their associated tools at different instants, by connecting a second motor, for example, M2, through the multiple switch 65, with switch 60 open, with similar valve structure supplied by phase B through conductors b and o. In this case the tools 42, for example, will be struck thesame number of times per unit of time, but not at the same instants.

In Fig. 9 the tie 58 and rails 59 are shown in plan with the motors M1 and M2 used at one end of the tie 58, on opposite sides thereof, causing either simultaneous or dissimultaneous' actuation of the tools 42, de-` pending upon whether the switch 60 be closed with switch 65 open, or the switch 65 closed and switch 60 open. Simultaneously, at the other end of the tie, onopposite sides thereof, there may be used tamping tools operated by the motors M3 and M4, whose tools 42 may be struck either simultaneously or at different instants.

yOr two toolsdriven, for example, by motors M1 and M3, on the same side of a tie, at opposite ends or at different positions longitudinally thereof, may have their tools 42 -either simultaneously or dissimultaneously struck by the motor mechanism.

Or a pair of motors M2 and M3, on opposite sides of the tie, and at differentpositions longitudinally thereof, may have their tools 42 either' simultaneously or dissimultaneously struck.

For procuring long high power strokes, the effectiveness of a motor increases in general with decrease in the frequency of the movement of the core or moving system. For efficient operation it is necessary that the moving system shall have given up substantially all of its kinetic energy. by impact upon the tool and imparted to the movingsy/stem on its forward stroke by the motor winding, as 6, before there is exerted upon the movingsystem a force causing its' return' stroke, 4which* force, generally, and in the example herein indicated, is applied by a second winding, such as 5. In reciprocating motors utilized for drilling stone or the like, short movement only of the tool is necessary', and high frequency operation is p allowable and may be attained with either energy of the moving systemshould be great, and this depends upon two factors, the square of the velocity at the time of impact, and the mass ofthe moving system. Long stroke is favorable to high power in that the longer the stroke the more vreadily may the velocity reach a suitably high magnitude,

since the acceleration period is longer, and

for longer acceleration period longer air gap is required.. It is preferred 'that of the kinetic energy (.5Ww2) the factor of velocity` squared (e2) shall predomiate over the mass factor (m), which means that high velocity is desirable with as light a moving system as consistent with procuring the desired kinetic energy. A light weight moving system is procurable by making the magnetizable core short and/or decreasing its cross section, but the crosssection ofthe magnetizable core cannot be reduced too far, and should not be reduced to the point where excess magnetic saturation occurs. and reduction of length` of core are contributed to by bringing the two air. gaps closer together, as described in connection with Fig. l.

Proportions of the general character last above referred to are suited for long higher power strokes, in ballast or tie tamping, cart-h tamping, and other fields, when there is utilized in addition low frequency energization of the motor winding or windings.

Long stroke For ballast or t-ie tamping in particular, it I hasbeen found that the frequency of energization Iof the winding 6, or both windings 5 and 6 when both are used, should be at the rate of about 20 per second, and at any rate, should lie within the range from about l5 to about 27 per second. Too low frequency causes too heavy an impact, other things remaining the same, and in ballast or tie tamping this impact should not be allowed,O to attain a magnitude which fractures the broken stone or ballast. On the other hand, the frequency of'operation should not be too high, for then the power of a blow or impact is too low. Within the range stated, and particularly at `or about 2O strokes per second, best operation is obtainable.

This low frequency may be obtained by utilizing an alternating current whose frequency is equal to the frequency of operation of the moving system of the motor, or sourcesof higher frequency current may be utilized and several impulses grouped t0 eifect low frequency motor operation. For a long high power stroke tool of the character herein described, operating at a frequency from about 15 toabout 27 strokes per second, the stroke of the-moving system is not less than 1% inches, nor in excess of 21/2 inches, the weight of the mov ing systemnot greater thanl four pounds and not less than two pounds, the ratio of the length of the magnetic core 24 itself to its diameter should fall within the limits of 3 to 2 and 3 to 1, and the ratio of the length of the air gap (between pole tips measured at the inside of the barrel 1). jto the length of stroke should lie between l to 3 and 2 to 3. When these relations obtain, long high power strokes for ballast or tie tamping are available at proper frequency, with impact sufficiently great l-eiliciently to perform the work and yet not fracture the broken stone or ballast.

For procuring suitably light weight or mass ofV the moving system, `the magnetic core 24 may be circumferentially grooved intermediate its ends, as indicated in Fig. 1. Or it may otherwise be lightened, as by longitudinally extending grooves in its outer surface, which grooves serve also to lengthen the paths of waste currents induced in the- It is preferable also in a sys-v core proper. tem such as indicated in Fig. 1 that the diameter of the non-magnetic guide rods25 and 26 should not be more than one-half the diameter of the core member 24. In general, the shorter vthe air gap, the .greater may be the diameter of the non-magnetic guide rods with respect to the diameter of .the magnetic core 24, with-the proviso, however, that the .cross section of the magnetic core shall not be made so small that 'ex- 'cesslve magnetic saturation occurs.

. The farther apart the air gaps', the more the magnetizable core, as member 24,' may be lightened by removal of material intermediate its ends, by circumferential orlongitudinal groove or groovesor otherwise; that is, the greater the distance between the air gaps, which is the distance between opposite ends of the central pole tips 3, Fig. 1, the longer and/or deeper may be the groove or grooves'between the ends of the core member 24 in reducing its weight. This is particularly of advantage'to adapt a reciprocating motor of a given design or structure, suitable for operation at a given frequency, at a given voltage, to operate f satisfactorily upon a supplycircuit of lower voltage. At lower voltage the magnetic energy or forces are less, and, therefore, to maintain the velocity of the core or moving core system sufficiently haigh to procurethe high'power blow or impact, the c ore may be lightened by so removing material, or by removing still more material from a core .which already hasbeen grooved or similarly lightened. Under these circumstances of lightening of' core, the velocity is mamtalned at the high order of magnitude desirable and gie mass only is reduced whereby the desiredl 1 gh order .of magnitude of blow or impact is substantially maintained.

As above, indicated, for a portable motor or tool it is desirable that the'weight be reduced by using materials of low specific gravity, such as aluminum alloy of the aforeance than copper, thereby eifecting an in' crease in the ratio of the inductance to the resistance of each winding, with consequent increased power factor and, when a common magnetic core member, aslaminations 3, is utilized, the induction losses therein are also reduced, more particularly in that the overlap of the current waves in the two windings 5 and 6 is diminished.

f By so utilizing aluminum conductor for the windings' and '6, and by utilizing aluminum alloy for the 'barrel and other parts of the apparatus, the weight is reduced from about 5 ounds, for example, to about 55 pounds, t e reduction in weight being in excess of 25 per cent.

l Furthermore, the utilization of aluminum l or the like for the conductor of the windings 5 and G materially reduces their inertia well below that of co per windings, and in consequence, the a uminum windings are to far lesser degree subject to displacement or loosening incident to the repeated impactsy impact block .45.

What I 4claim is:4 1. portable reciprocating motor comprising the'combination with a reciprocating core,system, electro-magnetic means for actuating said system, andv structure enclosing them, of an operators handle offset laterally from the ath of movement of said -core system an adjacent one end thereof, and a buffer springv receiving the impact of said core system vand of the moving system upon the tool and the .100

from said enclosing structurel visibly disposed outside ofA said enclosing structure beyond said handle.

, 2. A portable ,reciprocating motor comprising the combination with a reciprocating core system', electro-magnetic means for actuating said systemJ and an enclosing casing therefor, of a closure-member at one end of said casing, an operators handle carried by said closure member and oisetlaterally from the path of' movement of said core system and having a grip member disposed substantially in a plane normal to said path of movement of sald moving system, and a buiier spring receiving the impact vof said core system and visibly disposed beyond said handle outside of the motor.

3. A portable reciprocating motor com prising the combination with a` reciprocating l core system, electro-magnetic means for ac- A- therefor, of a member for closing the end of tuating said system, and structure enclosing them, of an operators handle disposed adjacent one end of said enclosing structure, a second handle secured to the motor s aced from and disposed beyondy the enc osing structure and .said first named handle, and a buffer spring receiving the impact of said core system disposed exteriorly of said enclosinfr structure intermediate said handles. 4. portable reciprocating motor comprising the combination with a reciprocating core system, electromagnetic means for actuating said system, and structure enclosing them, of a member secured to said enclosin structure and spaced from one end thereo a buffer spring visibly disposed between said member and said end of said enclosing structure and receiving the impact of said core system, and a handle carried by said meinber and disposed at a point more remote from the end of said closure structure than said spring.

5. A vportable reciprocating motor comprising the combination With a reciprocating core system, electroinagnetic means for actuating said system, and an enclosing casing therefor, ofa member for closing the end of said casing, tie rods for holding said end closure member to said casing, a second mem" .ber secured by said tie rods, and a handle carried by said second member and disposed at a )oint more remote from said end closure mem er than said second member.

v. 6. A portable reciprocating motor comprising the combination With a reciprocating core system, electro-magnetic means for actuating said system, and an enclosing casing said casing, tie rods dior holding said end closure member to said casing, a second member secured by said tie rods and spaced beyond said end closure member, a handle carried by said second member and disposed at j a point more remotefrom said end closure member than said second member, and a buffer spring receiving theA impact' of said coreA system visibly disposed between said second member and said end closure member.

7 A portable reciprocating motor comprising the combination with a reciprocating core system, electro-magnetic means for actuating said system, and an enclosing casing therefor, of a member for closing the end of said casing,`tie rods for holding said end closure member to said casing, a second mem'- ber secured by said tie rods, a handle carried byisaid second member and disposed at a point more remote from said end closure member than said second member, and a side handle dis vosed substantially at right angles to said iiandle carried by said end closure member. Y

8. A movable core system for a reciprocating electric motor, comprising a magnetic core member, rod structure of non-magnetic Y f, manganese steel secured thereto and projecting beyond the end thereof, and a shoe of hard impact-resisting metal welded upon the impact end of said rod structure.

9. A movable coresystem for a reciprocating electric motor, comprising a magnetic core member having a bore, and rod structurc of non-magnetic metal disposed in said bore and projecting beyond said core member, and a weld, integrally joining said core member and said rod structure.

10. A reciprocating motor comprising the combination with a reciprocatin core system, of a memberv Within which t e core system moves, magnetizable elements of a magnetic circuit disposed outside of said member, and clamping means secured to said member to hold-said magnetizable elements, said clamping means being subdivided to reduce the current -induced therein. ,d

l 11. A reciprocating motor comprising the combination with a reciprocatin core system, of a member Within which t e core system moves, magnetizable elements of a magnetic circuit disposed outside of said member, and clamping means extending circumferentially about the axis of movement of said core system and secured to said member for Iholding said magnetizable elements, said clamping `means divided circumferentially into a circumferential series. of clamping members for reducing the current induced therein. l y

12. A reciprocating motor comprising the combination with a reciprocating core system, of a member within which the core system moves, magnetizable elements of a magnetic circuit disposed outside of said member, and clamping means extending circumfereh; tially about the axis of movement of said core system and Secured to said member forA holding said magnetizable elements, said 'clamping means divided circumferentially` into a circumferential sries of clamping members for reducing the current inducedA therein, each of said clamping members securing a plurality of groups of said magnetizable elements.

13. A reciprocating motor comprising the combination with a reciprocating core system, of an actuating winding therefor, a

lon

member within said winding and within which the core system moves, magnetizable elements of a magnetic circuit disposed out-Y side of said member, and clampin means secured to said member to hold sai magnetizable elements, said member being'subdivided circumferentially of the axis of movement of said core system for reducing the current induced in member.

14. A reciprocating motor `comprising the combination with a reciprocating core system,

of a member Within which the core system v moves, magnetizable elements of a magnetic circuit disposed outside of said member, and

clamping means secured to said member and holding said magnetizable elements, said clamping means and said member being subdivided cimcumferentially of theaxis of 5 movement of said core system, the subdivi- Lsions ,of said member and said clamping means being so positioned with respect to each other circumferentially of said axis of movement of said core system as to reduce l the induced current. l

15. A reciprocating motor comprising a tubular member, a reciprocating core system movable therein, the exterior of said tubular member being polygonal troafford a plurality l of circumferentiallyspiced flat' faces, and a group of magnetic field laminations abutting edgewise against each of said faces. 16. A reciprocating motor comprisingra tubular member, a reciprocating core system movable therein, the exterior of said tubular member-being pol gonal to afford a plurality of circumferentia ly spaced flat faces, groups of magnetic field laminations extending substantially parallel with the axis of movement 5 of said core system yand abutting edgewise against said faces, and a clamping member common to a plurality of said groups of laminations and secured, directly to said a0 tubular member. f

motor having a reciprocating core system and electro-magnetic means for actuating the i same, of a bearing member vfor guidingsaid. i core system, a tool holder secured to said motor, a tool having a" shank disposed in said holder, a ycollar on said shank, and means for positioning said bearing member and limiting the movement of said tool with respect to said tool holder.V v

l0 18. A reciprocating motor `comprising a movable core system,.electromagnetic means for actuating the same, and a tubular member within which said core system reciprocates, clamping means secured Vto said l5 member and holding said electro-magnetic means, said tubular member consisting loi metal of low specific gravity and of a relatively high specific resistance as Ycom-l pared with copper, whereby the weight of the motor is decreased and induced current losses reduced.

19. A reciprocating motor comprising a reciprocating core system, and an energizing winding therefor of conductor having low specific gravity and high specific resistance as compared with copper.

20. A reciprocating` motor cgmprising a reciprocatingcore s stem, and an energizing winding therefor o conductor of aluminum.

50 21. A reciprocating motor comprising a reciprocating core system, 1a plurality 'of energizing windings, and a magnetizable structure forming an element ,common the magnetic circuits of said windings, said windings constituted of conductor having 17. The combination with a reciprocating 1 disposed outside of said tubular member, a

winding of aluminum conductor operatively related with said laminations and said core system, clamping members on said tubular member between which said laminations and said winding are held, whereb there is formed a unit comprisin said tu ularjmemf bei', laminations and sai winding.

24. A reciprocating motor comprising a tubular member of aluminum alloy, a core system movable within said tubular member., magnetic eld laminations disposed outside of said tubular member,' `a winding of aluminum conductor operatively related with said laminations andv said 4core system, and members on said tubular member between held, whereiy there is formed'. a unit comprising sai tubular member, laminations and said/winding. v

25. A reciprocating motor for producing long high power strokes, comprising a .magl net system having closely spaced air gaps, a relatively light core system having -a long stroke, and electro-magnetic meansv for ac-4 celerating the core system,I said means vbearing such relation to the Imass of said core system that the velocityimpartedthereto is relatively high. Y 26. yA reciprocating motor for producing long high power strokes, comprising a mag-k im y net system having closely spaced air gaps, a relatively light core system having a long stroke, electro-magnetic means for actuating said core system, and a source of current for l energizing said electro-magnetic means to `l l.'

produce from about lrto-about 27 strokes of said coresystem per second and to accelerate said core system within a stroke to a relatively high4 velocity.

27. A reciprocating motor for producing 12o long high power strokes, comprising a` magnet system having a plurality of closely adjacent air gaps, a relatively light reciprocating core system comprising a short magnetic core member producing a long stroke, eleci tro-magnetic windings producing', respec-'ltively, eii'ecting acceleration of a relatively high velocity.

said core system to 28. A percussve tool comprising 'a ballastl lauv which said laminations and said winding are magnetic fluxes in said air gaps and f tamper or other tool to be operated with long high power strokes, a Qreciprocating motor comprising a moving core system for impacting the tamper or other tool, said core system` having a weight lying within the range from about two to about four pounds,

-a magnet system having an air gap of such ,length as to effect a stroke of said system pounds, a magnet system having an air gap y of such length as to effect a stroke ofsaid system lying within the -range from' about 11/4 inches to about 21/2 inches, winding structure for energizing said magnet system,

' and a source of current for energizing sai winding to cause said core system to make `a number of strokes per second lying within the range from about 15 to aboutV 27 per second. c

30. A percussive tool comprising a ballast tamper or other toolv to be operated'with long high power strokes, a reciprocating motor comprising a moving` core system for impacting the tamper or other tool, said core system having a weight lyingV within4 the range from about two to about four pounds, the ratio of the length of the magnetic core member of said system to its vdisystem.

ameter falling within the range 'from about 1.5 to about 3, a magnet system having an air gaA of such length as to eifect a stroke of sai system lying within the range from aboutA 11/4c inches to about -21/2 inches, and Winding structure for energizing said magnet tamper or other tool to be operated with' long high power strokes, a reciprocating motor comprising a moving core system for impacting the tamper or other tool, said core. system having a weight lying within the range from about two to about four pounds,

the ratio of the length of the magnetic core member of said system toits diameter falling within the range from about 1.5 to about 3, a magnet system having anl` air gap of such length as to effect a -strokeei saidsystem lying wlthin the range from about 1%.

inches to about 2%. inches, winding struc- `ture for energizing said magnet system, and

a sourceof current for energizing said wind;`

ing to cause said core system to make a num-y.' berv of strokes'per second lying within the .i

range from about 15 to about 27 per second.

The combination of a movable core .member, anda vstop member to receivevvthe within which said core moves, a sleeve member engaging said tubular member, means abutting said sleeve to position it with respect to said tubular member, and a tool having a shank ,guided by said sleeve member.

' 34. A reciprocating motorvcomprising a movable' core system, a tubular member withink which said' core moves, a bearing member, asleeve member engaging said tubillar member, means abutting said sleeve to position said sleeve and bearing members Within said tubular member, and a member carried by said sleeve member to guide a tool shank. v 35. -An electric motor of thereciprocating type, comprising a reciprocatin impact element disposed to strike'a vwor ing tool on its forward stroke, actuating means therefor, and a resilient bu'er comprising a plurality of leaf springs for absorbing a sublstantial amountvof energy `from theimpact element. l

36. An electric motor of the reciprocating type comprising operating .mechanism including anlmpact element, an enclosing cas ingl therefor and a handle secured thereto, and a buffer for the impact element disposed externally of the casing and within the handle Iopening.

37. An electric motor of the reciprocating type comprisingy a movable impact member andactuating means therefor enclosed in a casing, a handle for the casing as a unit, and a buffer disposed underneath the handle and outside of the casing and provided with a guard for the-buffer to preclude injury to an operators hand'in lcase of damage v to the buffer.

' v38. An electric motor of the reciprocating type comprising a movable impact element, actuating means therefor, la buffer consisting of afplurality of leaf springs to absorb the energy of the impact element on its backward stroke, and an impact block resting against the springs and disposed in the path of' the impact element to be struck thereby.

' 39. An electric motor of the reciprocating type comprising a movable impact element,

actuating `means therefor, a. leaf springv bufer forfthe impact element, an impact block for transmitting the energy of the impact element to the buffer, and means for holding` the block between thev buii'er and the. im actelenient.

40. reci rocating motor'comprising a core, means or 4reciprocating said core comprising a Winding structure, groups of magnetizable elementsof a magnet-ic circuit as soc1ated withsaid winding structure, each'v of said groups of elements having pole tips 'disposed adjacent said core and spaced, respectively, unequal distances from the ends of said winding structure. f

41. A reciprocatory motor comprising a core, and means for reciprocating said core comprising at least three groups of magnetizable elements, each including a component extending longitudinally of said core and a row of poletips extending circumferentially thereof, intermediate and end rows of said pole tips being spaced, respectively, unequal distances from their components extending longitudinally of saidv core.

42. A reciprocatory motor comprising a core, and means for reciprocating said core comprising at least three groups of inagnetizable elements, each including a component extending longitudinally of said dore and a row of pole Atips extending circumferentially thereof, an end row ofsaid pole tips being spaced a' greater distance from its longitudinal component than is an intermediate row from its longitudinal component.

43. A motor comprising a core whose movement is unrestrained while'moving toward impact-delivering position with respect to a tool, means for reciprocating the core, a housing for the core, and a buffer disposed exteriorl upon the housing and adapted to absor energy from vthe core upon movement thereof from impact-deliverino position.

44. motor comprising a core whose movement is unrestrained while moving to-y ward impact-deliverin position with respect to a tool, means r reciprocating the core, a housing for the core, and a weblike buii'er disposed vexteriorly upon the housing transversely of the path of the core and adapted to absorb energy therefrom when it movesl from impact-delivering posi. tioii.

45. A motor comprising a reciprocatory core, means for reciprocating the core, a housing' forv the core,l and means for absorbing ener from the core upon movement thereo in one direction comprisinga web-like buffer extending transversely of the path of the core and whose ends are secured to said housing exteriorly thereof.

46. A motor comprising a reciprocatory core` means for reciprocating the core, a housing for the core, and means for absorbing energy from the ore upon movement thereof in 4one directionl comprising a web-like laminated spring buffer extending transversely of the path of the` core and whose ends are secured to said housing exteriorly thereof.

47. A reciprocating motor comprisingl the l combination with a reciprocating core system, of a member within which the core system moves, and magnetizable elements of system moves, magnetizable lelements of a.

magnetic circuit disposed around saidmem-- ber and having pole tips extending `therethrough and lying substantially flush with its internal bore, a winding for said magn etizablev elements, land a casing enclosing said winding and elements. l

'50. A reciprocating motor comprising a tubular barrel, bearings carried by said bar-4` rel, a reciprocating core having extensions slidable in said bearings, and magnetizable elements of amagnetic circuit disposed around said barrel and having pole tips extending therethrough and lying substantially Hush with its internal bore.

l51. A reciprocating motor comprising a *i tubular barrel, bearings carried by said barrel, a reciprocating'core having extensionsl slidable in said bearings, groups of magnetizable elements of a magnetic circuit disposed arouiid said barrel, each of said groups having pole tips extending through said barrel and lying substantially flush with its internal bore, a winding for two of said groups of magnetizable elements, and asecond winding for another of said groups of magnetizable elements and one of said two groups.

52. A reciprocating motor comprising the combination with a reciprocating core sy'stem, yof a member within which the'core system moves, groups of magnetizable 'elements of a magnetic circuit disposed around said member, a spacing plate between two of said groups, and means co-acting'with said member for forcing one of said lastnained groups against said spacing plate.

53. A reciprocating motor comprising the combination with a reciprocating core system, of a member Within which the core system moves, a group ofmagnetizable elements of a magnetic circuit disposed around said member adjacent its end, a second group of magnetizable elements disposed laround said member in a region removed from' lits end, a spacing platev between said groups,

and means co-acting with said member for v forcing said first-named group of elements against said spacing-plate.

54. reciprocating motor comprisingfzthe combination with a reciprocating core system, of a member within' which the core system moves, a group of magnetizable elements of a magnetic circuit disposedcaround said member adjacent its end, a second group of magnetizable elements disposed around said member in a region removed from its end, a spacing plate between said groups, a

for said means, a detachable plate adjacent said electromagnetic means for closing each them -to said casing.

' including groups' of magnetizab e elements--v *I pole tips on said elements, forming an air.'

end ofsaid casing, and/"means for securing said plates and casing together.

56. The combination with a reciprocating motor having a reciprocating core systemv and electromagnetic means for actuating the same, of a casing of magnetizable material for said means, a plate closing each end of said casing, and means comprising tie rods extending` through said plates for securing 57. A'. lreciprooatory motor comprising a core, and means for reciprocatin said core forming parts ,of a magnetic circuit, spaced gap in said magnetic circuit,4 said magnetizable element extending unequal distances longitudinally of said core so that said air gap is disposed towards one of said groups of magnetizable elements. 58. In a reciprocatory motor, a field structure surro-unding a movable core member comprising' a winding and group of magnetizable elements, pole tips on said elements forming air gaps-in a plurality of magnetic circuits, said pole tips being disposed to- Wards one group of magnetizable elements i for the purpose of shortening the distance longitudinally of said core between the respective air gaps. i

59. The combination with a motor comprising a core system and reciprocating.

means therefor, of a casing .for said means, handle structure clamped to said casing, and a member of deformable material interposed between the handle structure.

and casing.

60. The combination with a motor comprising a core system aand reciprocating means therefor, of a casing for said means, handle structure clamped to said casing, and a fibre disc interposed between the handle structure and casing.

61, A reciprocating motor comprising the combination with a reciprocating core system, ofa tubular member within which it moves, magnetic field elements outsidev of said member extending longitudinally thereof, and metallic clampin means engaging said ield elements for hoding them in predetermined fixed -relation with respect to said tubular member. v

62. 'A reciprocating motor comprising the combination with a reciprocating core system, of a tubular member within which the core system moves, magnetizable elements of a magnetic circuit disposed outside of said member, said elements constituting L-sha ed members having one leg thereof extending longitudinally of said tubular member, and mon-magnetic metallic securing means engaging said longitudinally extending legs and ositioning the -saine withvrespect to said tubu ar member.

63'. A reciprocating motor comprising the `combination with a reciprocating core system, of a tubular member within which the core system moves, groups of magnetizable elements disposed outside `of said member having componentsk extending both radially and longitudinally of said tubular member, and clamping. means for engaging both the longitudinally extending components and the tubular member for relatively 'positioning the same.

64. A reciprocating motor comprising the combinationl with av reciprocating core system, of a tubular member within which'the core system moves, grou s of magnetizable elements disposed outsidl of said member having components extending both radially and longitudinally/y of said core system, sqaid longitudinal components comprising magnetic poles having pole tips offset with respect thereto for interlocking with said tubular member, and clamping means engaging said poles and tubular member for relatively positioning the same.

65. A reciprocating motor comprising the combination Witha reciprocating core system, of a tubular member Within which it moves, groups of magnetizable laminae spaced circumferentially and longitudinally of said tubular member, the laminae of longitudinall spaced groups projecting toward each 'other longitudinally of said tubular member ,in pole-forming elements, and clamp structure secured to said tubular member and engaging said pole-formin elements to holdthem invpredetermined xed position with respect to said tubular member.

66. A reciprocating motor comprising the combination with a reciprocating core system, of la tubular member within which the vcore system moves, groups of magnetizable elements disposed outside of said member having components extending both radially and longitudinally of said core system, said longitudinal components comprising pole pieces cio-operating to form air gaps, clamping means bridging said air gaps and engaging said opposing pole pieces, and means for securing said clamping means with respect to said tubular member.

Y 67. A reciprocating motor comprising the combination with a reciprocating core system, of a tubular member Within which the core system moves, magnetizable elements disposed outside of said member having components extending both radially and longitudinally of said core system, said longitudinal components terminating in beveled faces adjacent an air gap, and Wedge-shaped clamping means engaging said faces and cooperating With said tubular member to position said magnetizable elements.

68. A portable recipro'catory motor com-- prising a barrel, shock-absorbing mechanism disposed adjacent one end of said barrel QERTIFICATE 0F G0 RRECTI 0N.

. r Patent No. 1,680,311.

ing actuated by said core, anda resilient member limiting the movement of said bushing with respect to said one of said end plates.

CARL S. WEYANDT,

CARL s'. VWEYANDr.

Itfis hereby certified that error appears in -the printed specification of the p 'above numbered patent,requirngvcorrectibn as: follows: Page '2; line 106, for

the word "tapping" read "tamping"; page-7, line 78, for "iuductancefread "re-- s t sistance", and.line 79, for "resistance" read "inductance"; page 9, line 66, claim Y 21, for the words "specific high" read "high'specfe'k and that the said Letters vPatent should be read with 4these'correctionsAtherein that the sam the record of the case in the Patent Office.

Signed and sealed this 13th day of August. A. D. 1929.

i (sai) M. J. Moore,

. i Acting comissioner of Patents,

Granted August 14, 1928, tol

e may conform to 

